Rotary electric contactors of the point-contact type



Jan. 21, 1969 R. PREUX 3,423,555

ROTARY ELECTRIC 'CONTACTORS OF THE POINT-CONTACT TYPE Filed April 20, 1967 Sheet of 2 Jan. 21, 1969 R. PREUX 3,

ROTARY ELECTRIC CONTACTORS OF THE POINT-CONTACT TYPE Filed April 20, 1967 Sheet 2 of 2 S 4 E E2 v United States Patent US. Cl. 200153 Int. Cl. H01h 3/00 ABSTRACT OF THE DISCLOSURE A rotary contactor comprising a first surface and a second surface capable of movement with respect to each other, said first surface being driven in rotation about a geometric axis which is movable in space while remaining parallel to itself, and at least one element carried by the periphery of said first surface, the shapes and relative movements of said surfaces being chosen so that the trajectory of said element is a cycloid, epicycloid or hypocycloid curve; and at least one electrical contact carried by said second surface and disposed at a position corresponding to one of the points of reflection of the trajectory of said element, whereby said contact is actuated by said element without friction or relative sliding movement of said surfaces.

The present invention relates to rotary electric contactors of the point-contact type.

In a large number of applications, it is necessary to actuate at regular intervals a plurality of electric contacts, and numerous devices have already been proposed to this end. These devices have however the serious disadvantage that the parts which have a relative movement and which come periodically into mutual contact, rub against each other or slide with respect to each other during the phase of contact. This results in rapid wear of these parts with a transfer of conductive materials to the insulating materials, which is liable to cause accidents within a short period of time.

In addition, the known devices have the disadvantage of comprising complicated and expensive switching systems, and these are also a source of frequent incidents.

The present invention has for its object rotary contactors which do not have the drawbacks referred to above, and which are distinguished to their advantage from known contactors by an extremely simple construction resulting in great safety of operation, remarkable ease of switching and an exceptionally long life of the device.

The rotary contactors with point-contacts according to the invention are essentially characterized in that they comprise two surfaces moving one with respect to the other, at least one of these surfaces being given a movement of rotation and comprising, at its periphery, active elements adapted to connect or to actuate contacts carried on the other surface, the forms of the said surfaces being such that the trajectories of the said active elements are curves with points of reflection of the cycloid, epicycloid or hypocycloid type, so that the said elements thus actuate or connect together the said contacts arranged at the points of reflection 'of the said trajectories, without friction or relative sliding action of the said surfaces.

In order to obtain the desired trajectories, it will for example only be necessary that, in cross-section along the plane of the trajectory, the first surface has a circular section, while the second surface has a circular or straightline section, the first surface rolling without sliding on the second surface.

Various forms of embodiment of the invention will be 3,423,555 Patented Jan. 21, 1969 ICC described hereinafter in detail, by way of nonlimitating examples, reference being made to the accompanying drawings, in which:

FIG. 1 illustrates diagrammatically the manner in which a hyocycloid is generated.

FIG. 2 is a transverse section of a first contactor in accordance with the invention, taken along the line II-II of FIG. 3.

FIG. 3 is a cross-section taken along the line III-III of FIG. 2.

FIG. 4 is a partial diagrammatic view of a contactor in accordance with the invention.

FIGS. 5 and 6 are partial sections of an alternative form of a contactor-reversing switch according to the invention, taken respectively along the line VV of FIG. 6 and along an axial plane.

FIG. 7 is a diagrammatic view of a detail of a further alternative form of the invention.

Referring to FIG. 1, there will be recalled the method of generating the hypocycloid. When a circle R, known as the rolling circle, having its center at 0, rolls without slip inside a fixed base circle C, each point of the rolling circle R describes a hypocycloid H. Thus, for example, when the center 0 occupies the positions 0 O O 0 after having moved through equal arcs a a 0: 0: the point n of the rolling circle 0 occupies successively the positions a a a and 11 as indicated in FIG. 1. The hypocycloid thus generated has a number of points of reflection located on the base circle and, in the case of FIG. 1, the points a and a, are two of these points of reflection.

When the rolling circle R does not move inside the base circle C but outside it, it generates an epicycloid. When it rolls on a straight-line base, it generates a cycloid. The epicycl oids and cycloids also have points of reflection in contact respectively with the base circle and the straightline base.

In its principle, the invention consists of arranging the contacts to be actuated or to be connected together on a base circle or on a straight-line base, at the positions of the points of reflection on the trajectory of an appropriate active element associated with a rolling circle, rolling without slip on the said circle or straight-line base.

It is clear that between the various points of reflection there is substantially no friction between the base circle and the rolling circle, since the relative movement of these parts is a movement of rotation without slip, and this is true irrespective of the speed of the rolling circle, that is to say the frequency of operation of the contacts.

The base circle or straight line constitutes the first surface, in the sense of the definition of the invention given above, while the rolling circle forms the second surface of appropriate shape.

In the forms of construction shown in FIGS. 2 to 7, the trajectory of the active elements which actuates or connects together the contacts is a hypocycloid, but the application of the invention to the case of a cycloid or an epicycloid will be obvious to those skilled in the art.

In the form of construction shown in FIGS. 2 and 3, a first fixed surface serving as the base circle is constituted by a cylindrical frame A, inside which a driving shaft B, coaxial with the frame A, drives in rotation 21 moving frame D.

On this frame is pivotally mounted, about a geometric axis X-X, a second surface formed by a member E, of which a first portion E serves as the rolling circle, its periphery R being toothed and co-operating in the same way as a gear with a toothed wheel A carried by the fixed frame A. A second portion E of the member E comprises arms provided, at a distance from the axis XX equal to the radius of the rolling circle through which passes the portion E with active conductor ele ments, four in number in the case of the drawings, C C C C adapted to establish a contact between pairs of terminals M M M M M M etc., which project from the interior of the fixed frame A, at positions such as P and P corresponding to the points of reflection of the cycloids such as H which constitute the trajectories of the conducting elements C C C and C Each of these conducting elements, upon reaching the points of reflection of its trajectory, thus momentarily closes the electric circuit between the terminals corresponding to these points.

There may of course be provided more than two terminals at each of the positions corresponding to the points of reflection of the trajectories of the conducting elements and it is possible to provide on the portion E of the moving frame E, any desired number of conducting elements, uniformly distributed or otherwise at the periphery of this frame.

There may also be employed a plurality of moving members such as E provided with conducting elements and associated with the same rolling circle, without departing from the scope of the invention, each of the moving members co-operating with a group of terminals arranged at suitable positions. Finally, it is possible to utilize any other driving means for the moving frame E without departing from the scope of the invention.

In the forms of construction shown in FIGS. 4 to 7, it will however be assumed for the sake of simplicity of the description, that there are employed members of the type which have just been described with reference to FIGS. 2 and 3, the elements already described and carrying out the same functions having 'been given the same reference numbers.

In the reversing contactor shown diagrammatically in FIG. 4, the portion E of the moving frame comprises one or more arms carrying, not conducting elements but one or more active elements which may or may not be conducting, adapted to push back flexible blades such as L carried by the fixed frame A and arranged in positions corresponding to the points of reflection of the trajectory of the elements D The flexible blades form part of a circuit comprising terminals such as C and carried by the fixed frame.

In the position of rest, each of the blades L closes the circuit corresponding to the terminal C but when the element D reaches the point of reflection of the hypocycloid which it describes, it pushes the blade L away from the terminal C and applies it against the terminal C The element D continuing its trajectory, the flexible blade L is no longer urged in the direction of the terminal 0-; and returns by its own elasticity to be applied against the terminal C The alternative form shown in FIGS. 5 and 6 is similar in all respects to that which has just been described with reference to FIG. 4, the flexible elements T playing the parts of the flexible blades L previously described. However, for the purpose of preventing any contamination of the terminals C and C these are housed inside a cavity P of the fixed frame A, inside which also moves the extremity of the element T which effects the contact with the terminals.

Finally, FIG. 7 illustrates an extremely simple application of the invention, in which an active element D carried by the portion E of the moving frame E, actuates as it passes, without sliding or friction, a push-button P of an independent contactor G, the push-button P being arranged on the fixed frame A at a point of reflection of the trajectory of the element D The same element D can of course operate a number of conductors arranged on the fixed frame at different positions, corresponding to different points of reflection on its trajectory. Similarly, the moving member C may be provided with a plurality of arms carrying elements D actuating respectively one or a plurality of separate contactors.

As has already been indicated, the invention includes all the alternative forms in which the active elements follow trajectories with points of reflection, of the cycloid, hypocycloid and epicycloid types, for the purpose of actuating contacts without friction or sliding action, irrespective of the method of rotational drive of the members carrying the said active elements.

The advantages presented by the invention are as follows:

The active elements of the moving surface can move at very high speed without appreciable wear of these elements and of the contacts with which they co-operate;

The active elements apply a very high pressure against the contacts, even if the rotational driving couple of these elements is small;

The contactor may not comprise any insulating member.

What I claim is:

1. A rotary contactor comprising a first surface and a second surface capable of movement one with respect to the other; means for driving said first surface in rotation about a geometric axis which is displaced in space while remaining parallel to itself; at least one element carried by said first surface at its periphery, the shapes and the relative movements of said surfaces being selected so that the trajectory of said element is a curve chosen from the group consisting of cycloids, epicycloids and hypocycloids; and at least one electrical contact carried by said second surface and disposed at a position corresponding to one of the points of reflection of the trajectory of said element, whereby said contact is actuated by said element without friction or relative sliding movement of said surfaces.

2. A rotary contactor comprising a first surface and a second surface capable of moving one with respect to the other, said second surface comprising a fixed cylindrical frame and said first surface being housed inside said second surface; a driving shaft coaxial with said fixed frame and driving in rotation a moving frame on which said first surface is pivotally mounted about a geometric axis parallel to the axis of said shaft; at the periphery of one portion of said first surface, teeth cooperating as a gear with a toothed ring carried by said fixed frame; at least one active element carried by said second surface and arranged in such manner that its trajectory is a hypocycloid; and at least one electrical contact arranged inside said fixed frame at a position corresponding to a point of reflection of said trajectory, whereby said contact is periodically acutated by said active element without friction or relative sliding movement of the two surfaces.

3. A rotary contactor as claimed in claim 2, in which said active element is a conducting element carried by an arm of said second surface, while said cont-act comprises at least two electrical terminals adapted to be connected to each other by said element.

4. A rotary contactor as claimed in claim 2, in which said active element is a conducting or non-conducting element carried by an arm of said second surface, while said contact comprises a flexible blade and a first terminal and a second terminal, said blade being in contact with said first terminal in the absence of external force but being capable of movement under the force applied by said element so as to come into contact with said second terminal, and then to return to its initial position by its own elasticity when it is no longer subjected to force.

5. A rotary contactor as claimed in claim 2, in which said active element is a conducting or non-conducting element carried by an arm of said second surface, while said contact comprises a flexible blade, and a first terminal and a second terminal; housed in a cavity of said fixed frame partially insulated from said second surface, said blade being in contact with said first terminal in the 5 6 absence of external applied force, but being capable of References Cited movement under the force applied by said element so as UNITED STATES PATENTS to come into contact with said second terminal and returning to its initial position by its own elasticity when it is not subjected to any external force. 5

6. A rotar contactor as claimed in claim 2, in which y ROBERT K. SCHAEFER, Primary Examlner.

said contact is constituted by a push-buttom of a contactor. H. BURKS, Assistant Examiner.

1,497,582 6/1924 Petersen ZOO-153.16 1,563,753 12/1925 Krone 200153.16 

